Question

A child of an O-group has a B-group father. The genotype of father will be
A) $I^OI^O$
B) $I^BI^B$
C) $I^AI^B$
D) $I^BI^O$

Answer 1

By our birth ancestors, blood types are inherited in the same manner as skin colour and other genetic characteristics. The A and B genes are co-dominant within the ABO Blood Group structure, that is, they are expressed if the gene is present. The O gene is silent and expressed only when there is neither A nor B present.

Complete answer:
Codominance means that no allele will mask the presence of the other allele. The ABO blood group, where alleles A and alleles B are also expressed, will be an example of humans. So they have blood type AB if a person inherits allele A from their mother and allele B from their father.
The best example of codominance is ABO blood group. The blood grouping of ABO is dominated by gene I, which has three A, B, and O alleles and shows codominance. Both A and B are recessive of the An O allele. The alleles of A and B codominant with each other. They have type AB blood where an individual has both A and B. If the alleles in the homologous chromosomes are dominant or recessive in codominance does not matter. If the homologous chromosome consists of two protein-producing alleles, then both are formed and form a phenotype or trait distinct from that of a homozygote.

$I^OI^O$- O blood group
$I^BI^B$- B blood group
$I^AI^B$- AB blood group
$I^BI^O$- B blood group

Hence, the correct answer is option (D)

Note: The most rare of the eight major blood groups is AB negative - about 1 percent of our donors have it. The need for AB negative blood is low despite being rare, and we are not struggling to locate donors with AB negative blood. Some blood forms, however, are both rare and in demand.